Motion-transmitting apparatus

ABSTRACT

APPARATUS FOR OPERATING ONE OR THE OTHER OF TWO LIMIT SWITCHES IN RESPONSE TO A MECHANICAL MOVEMENT AT A REMOTE POINT. A MASTER UNIT HAS A FIRST MEMBER MOVABLE IN OPPOSITE DIRECTIONS FROM A NEUTRAL POSITION IN RESPONSE TO THE MECHANICAL MOVEMENT, THE DIRECTION OF MOVEMENT OF THE MEMBER DEPENDING UPON THE DIRECTION OF THE MECHANICAL MOVEMENT. A SLAVE UNIT HAS A SECOND MEMBER MOVABLE IN OPPOSITE DIRECTIONS FROM NEUTRAL AND ADAPTED TO EFFECT THE OPERATION OF ONE OR THE OTHER OF THE SWITCHES DEPENDING UPON THE DIRECTION IN WHICH IT IS MOVED. A SINGLE PUSH-PULL LINEAR MEMBER OR CABLE TRANSMITS THE MOVEMENT OF THE FIRST MEMBER TO THE SECOND MEMBER IN EITHER DIRECTION.

United States Patent 3,570,323 MOTION-TRANSMITTING APPARATUS Donald E.Learmont, Rochester, Mich., assiguor to Verstand Engineering, Inc.,Madison Heights, Mich. Filed May 1, 1969, Ser. No. 820,915 Int. Cl. F16c1/10 U.S. Cl. 74-501 4 Claims ABSTRACT OF THE DISCLOSURE Apparatus foroperating one or the other of two limit switches in response to amechanical movement at a remote point. A master unit has a first membermovable in opposite directions from a neutral position in response tothe mechanical movement, the direction of movement of the memberdepending upon the direction of the mechanical movement. A slave unithas a second member movable in opposite directions from neutral andadapted to effect the operation of one or the other of the switchesdepending upon the direction in which it is moved. A single push-pulllinear member or cable transmits the movement of the first member to thesecond member in either direction.

SUMMARY OF THE IINVENTION It is a primary object of this invention toprovide an improved motion-transmitting apparatus for operating limitswitches or the like.

Another object is to provide a motion-transmitting apparatus responsiveto signals in two directions, to trip either one of two limit switches.

Another object is to provide a system in which the switches are disposedin a readily accessible position in full view for easy adjustment.

Another object is to provide a push-pull cable connection between theunits of the motion-transmitting apparatus which may be quickly coupledand uncoupled.

Another object is to provide a remote control system which is designedto utilize switches of various different constructions and/or brands.

Another object is to provide a system for the remote control of limitswitches that utilizes a longer stroke to trip the switches than manyother existing remote systems.

Another object is to provide a motion-transmitting apparatus having amaster head for receiving the signals and a slave head for applying thesignals to the switches, the heads being of substantially the sameconstruction.

Another object is to provide an improved master and slave headconstruction.

Another object is to provide a remote control operator of improvedconstruction making it possible to place the limit switches in aprotected zone removed from the location where the signals are produced.

Another object is to provide a master and slave head constructionadapted to transmit and receive signals in two different directionsutilizing a single cable, whereby to operate one or the other of twolimit switches depending upon the direction of the signal, the headsbeing normally spring centered to a neutral position.

Another object is to provide a master head construction having acentering spring for normally maintaining the trip arm in neutralposition, the centering spring through the action of the push-pull cablealso centering the trip arm of the slave head.

Another object is to make it possible to replace troublesome in-fieldswitches by reason of the fact that the mounting dimensions of themaster head are identical to many existing electrical switches.

3,570,323 Patented Mar. 16, 1971 Other objects and features of theinvention will become apparent as the description proceeds, especiallyWhen taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is an elevational view with parts broken away and in section ofremote control limit switch apparatus constructed in accordance with myinvention.

FIG. 2 is a longitudinal sectional view of the master head which is aportion of the apparatus shown in FIG. 1.

FIG. 3 is a fragmentary sectional view taken on the line 3-3 in FIG. 2.

FIG. 4 is a fragmentary sectional view taken on the line 44 in FIG. 2.

FIG. 5 is a fragmentary sectional view taken on the line 55 in FIG. 1.

Referring now more particularly to the drawings and especially to FIG.1, the apparatus there shown comprises a master head 10, a slave head12, a flexible pushpull linear member or cable assembly 14 fortransmitting motion from the master head to the slave head, and limitswitches 16 and 18 adapted to be operated by the slave unit.

The important use of this invention is in connection with limit switchcontrolled machine operations where it is desired to remove the limitswitches from the vicinity of the machine operation to be controlled inorder to protect the switches from contaminants such as cutting fluids,abrasive dusts or lubricants which might adversely affect the operationof the switches. In the present instance, the master head 10 is placednear the member which applies the mechanical movement or signal, and theslave head 12 and limit switches are located in a safe place far enoughremoved from the signal to be unaffected by adverse conditions in thevicinity of the signal and also in a place where they may be readilyaccessible for service or adjustment.

The master head 10 comprises an elongated upright housing 2'0 having aninternal chamber consisting essentially of an elongated cylinder 22which opens through the bottom of the housing and an enlarged portion 24communicating with the upper end of the cylinder. A piston or plunger 26is reciprocable vertically in the cylinder 22 of the chamber, havingheads 28 and 30 at the ends guided for vertical sliding movement in thefixed bearing sleeves 32 within the cylinder. The heads 28 and 30 areconnected by an integral reduced contral portion 34 which is surroundedby a compression coil centering spring 36. Free floating washers 38 and40 at the ends of the spring are adapted to bear against the bearingsleeves 32 and against the heads 2'8, 30. The piston 26 is thus heldnormally in the neutral position shown in FIG. 2 by the spring 36, butthe piston may be moved up or down from the neutral position compressingthe centering spring by the pressure of one of the heads 28, 30 pushingon the associated washer 38, 40.

The master head has a pivoted trip arm 42 which is secured upon a pivotpin 44 journaled for rotation in a bearing sleeve 46 in the upperportion of the housing 20. An O-ring seal 48 in an annular groove of thepin 44 is provided to prevent the entry of contaminants into the masterhea d housing.

A crank 50 which may be of the shape shown in FIG. 3 is secured to thepivot pin 44 by the pin 52 and carries a pin 54 upon which the slidablerectangular block 56 is pivoted. Block 56 is slidable in the horizontalgroove 58 formed in a fiat surface 59 of an enlarged upper end portionof piston head 28. Accordingly, oscillation in one direction or theother of pivot pin 44 by trip arm 42 will through the action of thecrank 50 and sliding pivot connection between the crank and piston 26result in raising or lowering piston 26.

The means for applying a signal to the master head is generallyindicated as a machine member 60 reciprocable as indicated by the arrowswhich is capable of moving the trip arm 42 in either direction from theupright neutral position shown in FIG. 1 by engaging the roller 61 onthe trip arm with either of the surfaces 61a or 61b of member 60. Thusthe master head is responsive to the mechanical movement of member 60when member 60 is at the extreme left or right of its completed travel,and the trip arm will then be moved in one direction or the otherdepending upon which direction the member 60 is moved. Member 60 isshown at its extreme right in dotted lines and at its extreme left indot-dash lines. (Switches indicate present status of movement.) Thus,referring to FIGS. 1 and 3, a clockwise movement of the trip arm 42'from the upright neutral position shown will cause the piston 26 to beraised, and counterclockwise movement of the trip arm 42 will cause thepiston '26 to be lowered.

The mechanical force of the member 60 ceases to be applied when member60 is in an intermediate position, at which time the trip arm 42 will bereturned to the neutral position shown by the action of the centeringspring 26. The member 60 may, for example, be a machine part which movesback and forth within limits and its completed travel will be indicatedby the signal of switches 16 or 18.

The slave head 12 including all of its parts, is of the sameconstruction as the master head except for the design of the trip armwhich instead of being like the element 42 of the master unit is of theconstruction shown and indicated at 70. Accordingly, it will beunnecessary to refer to the interior construction of the slave headexcept to say that it is exactly as shown in FIGS. 2-5. Correspondingparts of the two units will be referred to by the same numbers. However,the piston in the slave unit, corresponding to the piston 26 of themaster unit, may be centered by the centering spring 36 of the masterunit through the operation of the push-pull cable, making it unnecessaryto provide an individual centering spring 36 for the slave unit. Inother words, the slave unit may omit the centering spring 36 since itspiston will automatically follow the piston of the master unit and becentered by the centering spring of the master unit.

The trip arm 70 of the slave unit is secured midway between its endsupon the pivot pin 44 thereof and has switch operating elements 72 and74. These elements 72 and 74 are threaded members which thread into theopposite arms of the switch arm 70 for longitudinal or axial adjustment,and have heads 76, 78 for engaging the switch arms 80, 82 of theswitches 16 and 18. Hence rotation of the switch arm 70 in a clockwisedirection for example from the neutral position shown will cause thehead of element 72 to operate the switch arm 80 of switch 16, andreverse rotation of the switch arm 70 from neutral will cause the headof element 74 to engage switch arm 82 and thereby operate switch 18.

The motion of the piston in the slave head 12 will follow the motion ofthe piston 26 of the master head 10 from neutral by the operation of theconnecting push-pull cable assembly 14, although upward movement ofpiston 26 of the master head will result in downward movement of thepiston in the slave head and vice versa, as will be apparent. Pivotalmovement of trip arm 42 in direction A produces pivotal movement of triparm 70 in direction A, and movement of trip arm 42 in direction B causesmovement of trip arm 70 in the B direction. (See FIG. 1.) The cableassembly 14 includes a push-pull cable 14a. One end of the cable 140 hasa pilot head 90 on the end which fits in the lower end of the cylinder22 in housing of master head 10. An O-ring seal 92 in an annular groovein pilot head 90 excludes dirt and other foreign material from thehousing. The cable has an end 94 which is threaded to accept ascrew-type coupling member 96 having a head 98. The lower end of thepiston head 30 has a recess 100 which is enlarged at its inner extremityshown at 102 so as to provide a shoulder 104 to engage the underside ofthe head 98 of the inserted coupling 96. Thus the coupling 96 is firmlyanchored to the head 30 of the piston and follows its reciprocatorymovement. The side 106 of the recess 100, 102 is open however so that bymanually withdrawing the piston 26 far enough to Withdraw the recess100, 102 beyond the lower end of sleeve 32, the coupling member 96 maybe laterally withdrawn from the open side 106 of the recess to break theconnection. The parts may be just as easily assembled in a like manner.

The coupling or connection between the piston of the slave head 12 andthe opposite end of the cable will be understood to be exactly the sameas that described for the master head.

The push-pull cable 14a is sheathed in a flexible tubular cover 110which protects it and yet permits the cable to move axially within thecover. Annular flange plates 112 are secured to opposite ends of thecover 110. Mounting plates 114 slidable on the ends of the cover 110 areadapted to be bolted to the underside of the housing by fasteners 116 toclamp the flange plates 112 to the housing. It will of course beunderstood that before a coupling member 96 can be connected to ordisconnected from the piston of the head 10 or 12, the fitting 114 mustbe first detached from the housing.

It will thus be appreciated that movement of the piston 26 in the masterhead 10 from neutral in response to the movement of member 60 will betransmitted to the slave head 12 by the push-pull cable assembly 14 toeffeet a corresponding movement of the piston in the slave head, causingthe trip arm or lever 70 to pivot one way or the other and operate oneof the limit switches.

What I claim as my invention is:

1. The combination with two switches of motion transmitting apparatusfor operating one or the other of said two switches in response to amechanical movement at a point remote from said switches depending uponthe direction of said mechanical movement, comprising a master unitdisposed at said remote point and a slave unit disposed adjacent saidswitches, said master and slave units each including an elongatedhousing having a cylinder therein, a piston in each of said cylindersreciprocable in opposite directions from a neutral position, means fortransmitting the movement of one piston to the other comprising a singlepush-pull linear member having the ends thereof respectively connectedto said pistons, each unit having a pivotal trip arm on the housingthereof adapted to be pivoted in one direction or the other, meansconnecting the trip arm of each unit to the associated piston totransmit motion from one to the other, the trip arm of said master unitbeing adapted to be pivoted in one direction or the other by suchmechanical movement and the trip arm of said slave unit having meansrespectively engageable with said switches depending on the direction ofpivotal movement thereof, and yieldable means normally retaining saidpistons in their neutral positions comprising a spring within one ofsaid housings acting upon the piston therein.

2. The combination defined in claim 1, wherein the piston upon whichsaid spring acts is an elongated member having enlarged heads at theends, bearing sleeves slidably supporting said heads, washers freelyencircling said elongated piston member between said heads, said springbearing against said washers and pressing said Washers toward saidheads, said washers normally abutting said heads and said bearingsleeves to hold said elongated piston member in its neutral position.

3. The combination defined in claim 2, wherein said bearing sleeves arespaced apart the same distance as said heads.

4. The combination defined in claim 3, wherein the connection means forthe trip arm of each unit comprises a pin pivoted to said housing onwhich said trip arm is References Cited UNITED STATES PATENTS Shenton200-153.10X Oliner et a1. 74501 Morse 74501 Wolf 74-501 6 FOREIGNPATENTS 2/ 1952 Italy 74502 9/ 1905 Great Britain 74104 5 MILTONKAUFMAN, Primary Examiner U.S. C1. X.R.

